1. Field of the Invention
The present invention relates to an agitation mixer which performs agitation mixing by vibrating and/or rotating an agitator body.
2. Description of the Related Art
For example, in mixing processes which include adding a liquid to a powder, adding a powder to a liquid, or simultaneously adding a powder and a liquid, secondary agglomerates (“lumps”) of the powder are often produced in the liquid, and, once such lumps have been produced, re-dissolving them in the liquid is usually extremely difficult. In addition, the produced lumps often block a material inlet, often bringing about difficulties in subsequent feeding of a powder.
Accordingly, in recent years, apparatuses and methods capable of suppressing generation of secondary agglomerates during a process of mixing a powder and a liquid have been proposed.
In a continuous mixing device of the prior art, a rotary disc is installed in a casing having supply ports attached to an upper part thereof, for feeding a liquid and a powder, and a discharge port attached to a lower part thereof. The rotary disc separates the inside of the casing into an upper mixing chamber and a lower mixing chamber. Further, a scraper is attached to an upper area of the rotary disc, and a revolving scraper, which revolves independently of the rotary disc in a noncontacting manner, is mounted at a position below the rotary disc. A powder and a liquid fed from the supply ports are mixed by rotation of the rotary disc, and a resultant mixture brought into the lower mixing chamber is scraped off while being mixed by the revolving scraper, which rotates at a speed lower than that of the rotary disc, so as to be continuously transported to the outside via the discharge port (refer to, for example, Japanese Patent Laid-Open Publications Nos. Hei 11-19495, 2001-62273, and 2002-166154).
Further, a continuous mixing device for mixing powder and liquid by means of a rotary mixing disc, in which a liquid is fed in atomized form for uniform mixing of the powder and the liquid, is proposed in, for example, Japanese Patent Laid-Open Publications Nos. 2002-248330 and 2001-198447.
There is further proposed (in, for example, Japanese Patent Laid-Open Publication No. 2001-65850), a method for producing a slurry mixture by mixing a powder such as a coal powder and a liquid such as water. In this method, the powder is fed into a screw pump to which the liquid is further supplied in the midstream portion thereof to be mixed with the powder. The pressure in the screw pump is first boosted and then lowered at a discharge port for transforming the mixture into slurry.
Still further, the applicant of the present invention has proposed (in, for example, Japanese Patent Laid-Open Publication No. 2000-246131), a dispersing apparatus comprising a casing which can hold two or more materials therein, and a grinding spindle installed in the casing. In this dispersing apparatus, pits and projections are formed on at least one of the inner surface of the casing and the outer surface of the grinding spindle, and by reciprocating the grinding spindle in relation to the casing to produce a high pressure in a clearance between the inner surface of the casing and the outer surface of the grinding spindle, at least one out of the above-described two or more materials can be dispersed.
However, among the above-described mixing devices and mixing methods, there is no device and method capable of completely dissolving secondary agglomerates to thereby prevent blockage of a powder inlet. Further, in the above-described mixing devices and methods, limitations are imposed on combinations of powder and liquid to be mixed. Thus, the mixing often fails to achieve the desired quality.
Further, in the mixing devices and methods as described above, uniform mixing is likely to be insufficient in the case of a highly viscous material obtained by mixing, dissolving, chemical reaction, polymerization, or other treatment of liquids.